Method and apparatus for delivery of control signaling in a wireless communication system

ABSTRACT

A method and apparatus for delivery of control signaling in a wireless communication system are disclosed. In one embodiment, the method includes communicating with a UE (User Equipment) in the cell via downlink and uplink transmissions, wherein the downlink and uplink transmissions are organized into radio frames and each radio frame contains multiple subframes and each subframe contains multiple symbols. The method also includes transmitting, in the cell, a UE specific signal in a first symbol of a downlink control region of a subframe of the multiple subframes, wherein the network node is not allowed to transmit a common signal in the first symbol.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/174,716 filed on Jun. 12, 2015 and U.S.Provisional Patent Application Ser. No. 62/183,460 filed on Jun. 23,2015, the entire disclosures of which are incorporated herein in theirentirety by reference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to a method and apparatus for delivery of controlsignaling in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure is an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN). The E-UTRAN system can provide high datathroughput in order to realize the above-noted voice over IP andmultimedia services. A new radio technology for the next generation(e.g., 5G) is currently being discussed by the 3GPP standardsorganization. Accordingly, changes to the current body of 3GPP standardare currently being submitted and considered to evolve and finalize the3GPP standard.

SUMMARY

A method and apparatus for delivery of control signaling in a wirelesscommunication system are disclosed. In one embodiment, the methodincludes communicating with a UE (User Equipment) in the cell viadownlink and uplink transmissions, wherein the downlink and uplinktransmissions are organized into radio frames and each radio framecontains multiple subframes and each subframe contains multiple symbols.The method also includes transmitting, in the cell, a UE specific signalin a first symbol of a downlink control region of a subframe of themultiple subframes, wherein the network node is not allowed to transmita common signal in the first symbol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

FIG. 5 is a reproduction of FIGS. 5.1-1 of 3GPP TS 36.300.

FIG. 6 is a reproduction of FIGS. 5.1-2 of 3GPP TS 36.300.

FIG. 7 is a reproduction of FIG. 6.2.2-1 of 3GPP TS 36.211.

FIG. 8 is a reproduction of Table 6.2.3-1 of 3GPP TS 36.211.

FIG. 9 is a reproduction of Table 6.9.3-1 of 3GPP TS 36.211.

FIG. 10 is a reproduction of Table 6.10.3.2-1 of 3GPP TS 36.211.

FIG. 11 is a reproduction of Table 6.10.3.2-2 of 3GPP TS 36.211.

FIG. 12 is a reproduction of FIG. 10.1.5.1-1 of 3GPP TS 36.300.

FIG. 13 is a reproduction of FIG. 10.1.5.2-1 of 3GPP TS 36.300.

FIG. 14 is a reproduction of FIG. 3-2 of METIS Deliverable D2.4.

FIG. 15 is a diagram of a subframe according to one exemplaryembodiment.

FIG. 16 is a flow chart according to one exemplary embodiment.

FIG. 17 is a flow chart according to one exemplary embodiment.

FIG. 18 is a flow chart according to one exemplary embodiment.

FIG. 19 is a message diagram according to one exemplary embodiment.

FIG. 20 is a message diagram according to one exemplary embodiment.

FIG. 21 is a message diagram according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A orLTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra MobileBroadband), WiMax, or some other modulation techniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support the wireless technologydiscussed in the various documents, including: “DOCOMO 5G White Paper”by NTT Docomo, Inc. and METIS Deliverable D2.4, “Proposed solutions fornew radio access”. Furthermore, the exemplary wireless communicationsystems devices described below may be designed to support one or morestandards such as the standard offered by a consortium named “3rdGeneration Partnership Project” referred to herein as 3GPP, including:TS 36.300 V12.5.0, “E-UTRA and E-UTRAN Overall description”; 3GPP TS36.211 V12.5.0, “E-UTRA Physical channels and modulation”; TS 36.331V12.5.0, “E-UTRA RRC protocol specification”; TS 36.321 V12.5.0, “E-UTRAMAC protocol specification”; and TS 36.213 V12.5.0, “E-UTRA Physicallayer procedures”. The standards and documents listed above are herebyexpressly incorporated by reference in their entirety.

FIG. 1 shows a multiple access wireless communication system accordingto one embodiment of the invention. An access network 100 (AN) includesmultiple antenna groups, one including 104 and 106, another including108 and 110, and an additional including 112 and 114. In FIG. 1, onlytwo antennas are shown for each antenna group, however, more or fewerantennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112and 114 transmit information to access terminal 116 over forward link120 and receive information from access terminal 116 over reverse link118. Access terminal (AT) 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal(AT) 122 over forward link 126 and receive information from accessterminal (AT) 122 over reverse link 124. In a FDD system, communicationlinks 118, 120, 124 and 126 may use different frequency forcommunication. For example, forward link 120 may use a differentfrequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access network transmitting through a single antenna to all itsaccess terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, anevolved Node B (eNB), or some other terminology. An access terminal (AT)may also be called user equipment (UE), a wireless communication device,terminal, access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmittersystem 210 (also known as the access network) and a receiver system 250(also known as access terminal (AT) or user equipment (UE)) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain embodiments, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

Turning to FIG. 3, this figure shows an alternative simplifiedfunctional block diagram of a communication device according to oneembodiment of the invention. As shown in FIG. 3, the communicationdevice 300 in a wireless communication system can be utilized forrealizing the UEs (or ATs) 116 and 122 in FIG. 1 or the base station (orAN) 100 in FIG. 1, and the wireless communications system is preferablythe LTE system. The communication device 300 may include an input device302, an output device 304, a control circuit 306, a central processingunit (CPU) 308, a memory 310, a program code 312, and a transceiver 314.The control circuit 306 executes the program code 312 in the memory 310through the CPU 308, thereby controlling an operation of thecommunications device 300. The communications device 300 can receivesignals input by a user through the input device 302, such as a keyboardor keypad, and can output images and sounds through the output device304, such as a monitor or speakers. The transceiver 314 is used toreceive and transmit wireless signals, delivering received signals tothe control circuit 306, and outputting signals generated by the controlcircuit 306 wirelessly. The communication device 300 in a wirelesscommunication system can also be utilized for realizing the AN 100 inFIG. 1.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the invention. In thisembodiment, the program code 312 includes an application layer 400, aLayer 3 portion 402, and a Layer 2 portion 404, and is coupled to aLayer 1 portion 406. The Layer 3 portion 402 generally performs radioresource control. The Layer 2 portion 404 generally performs linkcontrol. The Layer 1 portion 406 generally performs physicalconnections.

Frame structure in LTE, as discussed in 3GPP TS 36.300, is organizedinto radio frames and each radio frame (e.g., 10 ms) is divided into tensubframes. Each subframe may include two slots:

5. Physical Layer for E-UTRA

Downlink and uplink transmissions are organized into radio frames with10 ms duration. Two radio frame structures are supported:

-   -   Type 1, applicable to FDD;    -   Type 2, applicable to TDD.        Frame structure Type 1 is illustrated in FIGS. 5.1-1 [which is        reproduced as FIG. 5 of the present application]. Each 10 ms        radio frame is divided into ten equally sized sub-frames. Each        sub-frame consists of two equally sized slots. For FDD, 10        subframes are available for downlink transmission and 10        subframes are available for uplink transmissions in each 10 ms        interval. Uplink and downlink transmissions are separated in the        frequency domain.        Frame structure Type 2 is illustrated in FIGS. 5.1-2 [which is        reproduced as FIG. 6 of the present application]. Each 10 ms        radio frame consists of two half-frames of 5 ms each. Each        half-frame consists of eight slots of length 0.5 ms and three        special fields: DwPTS, GP and UpPTS. The length of DwPTS and        UpPTS is configurable subject to the total length of DwPTS, GP        and UpPTS being equal to 1 ms. Both 5 ms and 10 ms switch-point        periodicity are supported. Subframe 1 in all configurations and        subframe 6 in configuration with 5 ms switch-point periodicity        consist of DwPTS, GP and UpPTS. Subframe 6 in configuration with        10 ms switch-point periodicity consists of DwPTS only. All other        subframes consist of two equally sized slots.        For TDD, GP is reserved for downlink to uplink transition. Other        Subframes/Fields are assigned for either downlink or uplink        transmission. Uplink and downlink transmissions are separated in        the time domain.

Furthermore, each downlink slot includes N_(symb) ^(DL) OFDM (OrthogonalFrequency Division Multiplexing) symbols as shown in FIGS. 7 and 8. FIG.7 is a reproduction of FIG. 6.2.2-1 of 3GPP TS 36.211. FIG. 8 is areproduction of Table 6.2.3-1 of 3GPP TS 36.211.

LTE has several physical layer downlink control signaling.MasterInformationBlock (MIB) provides necessary system information,including downlink bandwidth, system frame number, and PHICHconfiguration for UEs in the cell, as discussed in 3GPP TS 36.331 asfollows:

MasterInformationBlock

The MasterInformationBlock includes the system information transmittedon BCH.Signalling radio bearer: N/A

RLC-SAP: TM

Logical channel: BCCH

Direction: E-UTRAN to UE

-   -   MasterInformationBlock

-- ASN1START MasterInformationBlock ::= SEQUENCE {   dl-BandwidthENUMERATED { n6, n15, n25, n50, n75, n100} ,   phich-ConfigPHICH-Config,   systemFrameNumber BIT STRING (SIZE (8)),   spare BITSTRING (SIZE (10)) } -- ASN1STOP

MasterInformationBlock field descriptions dl-Bandwidth Parameter:transmission bandwidth configuration, N_(RB) in downlink, see TS 36.101[42, table 5.6-1]. n6 corresponds to 6 resource blocks, n15 to 15resource blocks and so on. systemFrameNumber Defines the 8 mostsignificant bits of the SFN. As indicated in TS 36.211 [21, 6.6.1], the2 least significant bits of the SFN are acquired implicitly in the P-BCHdecoding, i.e. timing of 40 ms P-BCH TTI indicates 2 least significantbits (within 40 ms P-BCH TTI, the first radio frame: 00, the secondradio frame: 01, the third radio frame: 10, the last radio frame: 11).One value applies for all serving cells of a Cell Group (i.e. MCG orSCG). The associated functionality is common (i.e. not performedindependently for each cell).

MIB is carried by the first 4 symbols in the second slot of the firstsubframe in a radio frame, as discussed in 3GPP TS 36.211 as follows:

6.6.4 Mapping to Resource Elements

The block of complex-valued symbols y^((p))(0), . . . ,y^((p))(M_(symb)−1) for each antenna port is transmitted during 4consecutive radio frames starting in each radio frame fulfilling n_(f)mod 4=0 and shall be mapped in sequence starting with y(0) to resourceelements (k,l). The mapping to resource elements (k,l) not reserved fortransmission of reference signals shall be in increasing order of firstthe index k, then the index l in slot 1 in subframe 0 and finally theradio frame number. The resource-element indices are given by

${k = {\frac{N_{RB}^{DL}N_{sc}^{RB}}{2} - 36 + k^{\prime}}},{k^{\prime} = 0},1,\ldots \mspace{14mu},71$l = 0, 1, …  , 3

where resource elements reserved for reference signals shall beexcluded. The mapping operation shall assume cell-specific referencesignals for antenna ports 0-3 being present irrespective of the actualconfiguration. The UE shall assume that the resource elements assumed tobe reserved for reference signals in the mapping operation above but notused for transmission of reference signal are not available for PDSCHtransmission. The UE shall not make any other assumptions about theseresource elements.

Synchronization signals (e.g., PSS and SSS) in a cell are designed forUEs in the cell to obtain the downlink timing, i.e. the radio frameboundary and subframe boundary. PSS (Primary Synchronization Signal) andSSS (Secondary Synchronization Signal) are each carried by one symbol.For example, for FDD (Frequency Division Duplex) system, PSS is carriedby the last symbol in slot 0 and 10, and SSS is carried by thesecond-last symbol in slot 0 and 10, where slot 0 and slot 10 are thefirst slot of the first subframe and that of the sixth subframe in aradio frame, as discussed in 3GPP TS 36.211 as follows:

6.11.1.2 Mapping to Resource Elements

The mapping of the sequence to resource elements depends on the framestructure. The UE shall not assume that the primary synchronizationsignal is transmitted on the same antenna port as any of the downlinkreference signals. The UE shall not assume that any transmissioninstance of the primary synchronization signal is transmitted on thesame antenna port, or ports, used for any other transmission instance ofthe primary synchronization signal.The sequence d(n) shall be mapped to the resource elements according to

a_(k, l) = d(n), n = 0, …  , 61$k = {n - 31 + \frac{N_{RB}^{DL}N_{sc}^{RB}}{2}}$

For frame structure type 1, the primary synchronization signal shall bemapped to the last OFDM symbol in slots 0 and 10.For frame structure type 2, the primary synchronization signal shall bemapped to the third OFDM symbol in subframes 1 and 6. Resource elements(k,l) in the OFDM symbols used for transmission of the primarysynchronization signal where

$k = {n - 31 + \frac{N_{RB}^{DL}N_{sc}^{RB}}{2}}$n = −5, 4, …  , −1, 62, 63, …  66

are reserved and not used for transmission of the primarysynchronization signal.

6.11.2.2 Mapping to Resource Elements

The mapping of the sequence to resource elements depends on the framestructure. In a subframe for frame structure type 1 and in a half-framefor frame structure type 2, the same antenna port as for the primarysynchronization signal shall be used for the secondary synchronizationsignal.The sequence d(n) shall be mapped to resource elements according to

a_(k, l) = d(n), n = 0, …  , 61$k = {n - 31 + \frac{N_{RB}^{DL}N_{sc}^{RB}}{2}}$$l = \left\{ \begin{matrix}{N_{symb}^{DL} - 2} & {{in}\mspace{14mu} {slots}\mspace{14mu} 0\mspace{14mu} {and}\mspace{14mu} 10} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 1} \\{N_{symb}^{DL} - 1} & {{in}\mspace{14mu} {slots}\mspace{14mu} 1\mspace{14mu} {and}\mspace{14mu} 11} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 2}\end{matrix} \right.$

Resource elements (k,l) where

$k = {n - 31 + \frac{N_{RB}^{DL}N_{sc}^{RB}}{2}}$$l = \left\{ {{{\begin{matrix}{N_{symb}^{DL} - 2} & {{in}\mspace{14mu} {slots}\mspace{14mu} 0\mspace{14mu} {and}\mspace{14mu} 10} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 1} \\{N_{symb}^{DL} - 1} & {{in}\mspace{14mu} {slots}\mspace{14mu} 1\mspace{14mu} {and}\mspace{14mu} 11} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 2}\end{matrix}n} = {- 5}},{- 4},\ldots \mspace{14mu},{- 1},62,63,{\ldots \mspace{14mu} 66}} \right.$

are reserved and not used for transmission of the secondarysynchronization signal.

Cell-specific Reference Signal (CRS) is for UEs to measure downlinkradio condition of the cell. The symbol carrying CRS depends on thenumber of CRS port. As an example, for a cell configured with two portCRS, CRS is carried by the first symbol and the third-last symbol inboth slots of a subframe, as discussed in 3GPP TS 36.211 as follows:

6.10.1.2 Mapping to Resource Elements

The reference signal sequence r_(l,n) _(s) (m) shall be mapped tocomplex-valued modulation symbols a_(k,l) ^((p)) used as referencesymbols for antenna port p in slot n_(s) according to

a _(k,l) ^((p)) =r _(l,n) _(s) (m′)

where

k = 6m + (v + v_(shift))mod  6 $l = \left\{ {{{\begin{matrix}{0,{N_{symb}^{DL} - 3}} & {{{if}\mspace{14mu} p} \in \left\{ {0,1} \right\}} \\1 & {{{if}\mspace{14mu} p} \in \left\{ {2,3} \right\}}\end{matrix}m} = 0},1,\ldots \mspace{14mu},{{{2 \cdot N_{RB}^{DL}} - {1m^{\prime}}} = {m + N_{RB}^{\max,{DL}} - N_{RB}^{DL}}}} \right.$

The variables v and v_(shift) define the position in the frequencydomain for the different reference signals where v is given by

$v = \left\{ \begin{matrix}0 & {{{if}\mspace{14mu} p} = {{0\mspace{14mu} {and}\mspace{14mu} l} = 0}} \\3 & {{{if}\mspace{14mu} p} = {{0\mspace{14mu} {and}\mspace{14mu} l} \neq 0}} \\3 & {{{if}\mspace{14mu} p} = {{1\mspace{14mu} {and}\mspace{14mu} l} = 0}} \\0 & {{{if}\mspace{14mu} p} = {{1\mspace{14mu} {and}\mspace{14mu} l} \neq 0}} \\{3\left( {n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} \right)} & {{{if}\mspace{14mu} p} = 2} \\{3 + {3\left( {n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} \right)}} & {{{if}\mspace{14mu} p} = 3}\end{matrix} \right.$

The cell-specific frequency shift is given by v_(shift)=N_(ID) ^(cell)mod 6.

Physical downlink control channel (PDCCH) signaling provides resourceallocation of downlink or uplink transmission, e.g., on PDSCH (PhysicalDownlink Shared Channel) or PUSCH (Physical Uplink Shared Channel).PDCCH is carried by one or several symbols in the beginning of asubframe depending on the signaling on PCFICH (Physical Control FormatIndicator Channel). For example, when PCFICH indicating the number ofsymbols used for PDCCH transmission in a subframe is 2, PDCCH is carriedby the first two symbols of the subframe, as discussed in 3GPP TS 36.211as follows:

6.8.5 Mapping to Resource Elements

The mapping to resource elements is defined by operations on quadrupletsof complex-valued symbols. Let z^((p))(i)=

y^((p))(4i),y^((p))(4i+1),y^((p))(4i+2),y^((p))(4i+3)

denote symbol quadruplet i for antenna port p.

The block of quadruplets z^((p))(0), . . . , z^((p))(M_(quad)−1), whereM_(quad)=M_(symb)/4, shall be permuted resulting in w^((p))(0), . . . ,w^((p))(M_(quad)−1). The permutation shall be according to the sub-blockinterleaver in clause 5.1.4.2.1 of 3GPP TS 36.212 [3] with the followingexceptions:

-   -   the input and output to the interleaver is defined by symbol        quadruplets instead of bits    -   interleaving is performed on symbol quadruplets instead of bits        by substituting the terms “bit”, “bits” and “bit sequence” in        clause 5.1.4.2.1 of 3GPP TS 36.212 [3] by “symbol quadruplet”,        “symbol quadruplets” and “symbol-quadruplet sequence”,        respectively        <NULL> elements at the output of the interleaver in 3GPP TS        36.212 [3] shall be removed when forming w^((p))(0), . . . ,        w^((p))(M_(quad)−1). Note that the removal of <NULL> elements        does not affect any <NIL> elements inserted in clause 6.8.2.        The block of quadruplets w^((p))(0), . . . , w^((p))(M_(quad)−1)        shall be cyclically shifted, resulting in w ^((p))(0), . . . , w        ^((p)) (M_(quad)−1) where w ^((p))(i)=w^((p))((i+N_(ID) ^(cell))        mod M_(quad)).        Mapping of the block of quadruplets w ^((p))(0), . . . , w        ^((p))(M_(quad)−1) is defined in terms of resource-element        groups, specified in clause 6.2.4, according to steps 1-10        below:    -   1) Initialize m′=0 (resource-element group number)    -   2) Initialize k′=0    -   3) Initialize l′=0    -   4) If the resource element (k′,l′) represents a resource-element        group and the resource-element group is not assigned to PCFICH        or PHICH then perform step 5 and 6, else go to step 7    -   5) Map symbol-quadruplet w ^((p))(m′) to the resource-element        group represented by (k′,l′) for each antenna port p    -   6) Increase m′ by 1    -   7) Increase l′ by 1    -   8) Repeat from step 4 if l′<L, where L corresponds to the number        of OFDM symbols used for PDCCH transmission as indicated by the        sequence transmitted on the PCFICH    -   9) Increase k′ by 1    -   10) Repeat from step 3 if k′<N_(RB) ^(DL)N_(sc) ^(RB)

Physical Hybrid ARQ Indicator Channel (PHICH) carries HARQ (HybridAutomatic Repeat reQuest) feedback in response to uplink transmissions.PHICH is carried by one or several symbols in the beginning of asubframe depending on the configured PHICH duration as well as thesubframe type. For example, for the case of a non-MBSFN subframe of aFDD cell with extended PHICH duration configuration, the PHICH iscarried by the first three symbols of the subframe, as discussed in 3GPPTS 36.211 as follows:

6.9.3 Mapping to Resource Elements

The sequence y ^((p))(0), . . . , y ^((p))(M_(symb) ⁽⁰⁾−1) for each ofthe PHICH groups is defined by

y ^((p))(n)=Σy _(i) ^((p))(n)

where the sum is over all PHICHs in the PHICH group and y_(i) ^((p))(n)represents the symbol sequence from the i:th PHICH in the PHICH group.PHICH groups are mapped to PHICH mapping units.

For normal cyclic prefix, the mapping of PHICH group m to PHICH mappingunit m′ is defined by

{tilde over (y)} _(m) ^((p))(n)= y _(m) ^((p))(n)

where

$m^{\prime} = {m\left\{ {\begin{matrix}{0,1,\ldots \mspace{14mu},{N_{PHICH}^{group} - 1}} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 1} \\{0,1,\ldots \mspace{14mu},{{m_{i} \cdot N_{PHICH}^{group}} - 1}} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}{\mspace{11mu} \;}2}\end{matrix},} \right.}$

and where m_(i) is given by Table 6.9-1.For extended cyclic prefix, the mapping of PHICH group m and m+1 toPHICH mapping unit m′ is defined by

{tilde over (y)} _(m′) ^((p))(n)= y _(m) ^((p))(n)+ y _(m+1) ^((p))(n)

where

m^(′) = m/2 $m = \left\{ \begin{matrix}{0,2,\ldots \mspace{14mu},{N_{PHICH}^{group} - 2}} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 1} \\{0,2,\ldots \mspace{14mu},{{m_{i} \cdot N_{PHICH}^{group}} - 2}} & {{for}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}{\mspace{11mu} \;}2}\end{matrix} \right.$

and where m_(i) is given by Table 6.9-1.Let z^((p))(i)=

{tilde over (y)}^((p))(4i),{tilde over (y)}^((p))(4i+1),{tilde over(y)}^((p))(4i+2),{tilde over (y)}^((p))(4i+3)

, i=0, 1, 2 denote symbol quadruplet i for antenna port p. Mapping toresource elements is defined in terms of symbol quadruplets according tosteps 1-10 below:

-   -   1) For each value of l′    -   2) Let n_(l′) denote the number of resource element groups not        assigned to PCFICH in OFDM symbol l′    -   3) Number the resource-element groups not assigned to PCFICH in        OFDM symbol l′ from 0 to n_(l′)−1, starting from the        resource-element group with the lowest frequency-domain index.    -   4) Initialize m′=0 (PHICH mapping unit number)    -   5) For each value of i=0, 1, 2    -   6) Symbol-quadruplet z^((p))(i) from PHICH mapping unit m′ is        mapped to the resource-element group represented by (k′,l′)_(i)        as defined in clause 6.2.4 where the indices k′_(i) and l′_(i)        are given by steps 7 and 8 below:    -   7) The time-domain index l′_(i) is given by

$\begin{matrix}{l_{i}^{\prime} = \left\{ \begin{matrix}0 & {{{normal}\mspace{14mu} {PHICH}\mspace{14mu} {duration}},{{all}\mspace{14mu} {subframes}}} \\{\left( {\left\lfloor {m^{\prime}/2} \right\rfloor + i + 1} \right){mod}\mspace{14mu} 2} & {{{extended}\mspace{14mu} {PHICH}\mspace{14mu} {duration}},{{MBSFN}\mspace{14mu} {subframes}}} \\{\left( {\left\lfloor {m^{\prime}/2} \right\rfloor + i + 1} \right){mod}\mspace{14mu} 2} & {{{extended}\mspace{14mu} {PHICH}\mspace{14mu} {duration}},{{subframe}\mspace{14mu} 1\mspace{14mu} {and}\mspace{14mu} 6\mspace{14mu} {in}\mspace{14mu} {frame}\mspace{14mu} {structure}\mspace{14mu} {type}\mspace{14mu} 2}} \\i & {otherwise}\end{matrix} \right.} & \;\end{matrix}$

-   -   8) Set the frequency-domain index k′_(i) to the resource-element        group assigned the number n _(i) in step 3 above, where n _(i)        is given by

${\overset{\_}{n}}_{i} = \left\{ \begin{matrix}{\left( {\left\lfloor {N_{ID}^{cell} \cdot {n_{l_{i}^{\prime}}/n_{1}}} \right\rfloor + m^{\prime}} \right){mod}\mspace{14mu} n_{l_{i}^{\prime}}} & {i = 0} \\{\left( {\left\lfloor {N_{ID}^{cell} \cdot {n_{l_{i}^{\prime}}/n_{1}}} \right\rfloor + m^{\prime} + \left\lfloor {n_{l_{i}^{\prime}}/3} \right\rfloor} \right){mod}\mspace{14mu} n_{l_{i}^{\prime}}} & {i = 1} \\{\left( {\left\lfloor {N_{ID}^{cell} \cdot {n_{l_{i}^{\prime}}/n_{1}}} \right\rfloor + m^{\prime} + \left\lfloor {2{n_{l_{i}^{\prime}}/3}} \right\rfloor} \right){mod}\mspace{14mu} n_{l_{i}^{\prime}}} & {i = 2}\end{matrix} \right.$

-   -   -   in case of extended PHICH duration in MBSFN subframes, or            extended PHICH duration in subframes 1 and 6 for frame            structure type 2 and by

${\overset{\_}{n}}_{i} = \left\{ \begin{matrix}{\left( {\left\lfloor {N_{ID}^{cell} \cdot {n_{l_{i}^{\prime}}/n_{0}}} \right\rfloor + m^{\prime}} \right){mod}\mspace{14mu} n_{l_{i}^{\prime}}} & {i = 0} \\{\left( {\left\lfloor {N_{ID}^{cell} \cdot {n_{l_{i}^{\prime}}/n_{0}}} \right\rfloor + m^{\prime} + \left\lfloor {n_{l_{i}^{\prime}}/3} \right\rfloor} \right){mod}\mspace{14mu} n_{l_{i}^{\prime}}} & {i = 1} \\{\left( {\left\lfloor {N_{ID}^{cell} \cdot {n_{l_{i}^{\prime}}/n_{0}}} \right\rfloor + m^{\prime} + \left\lfloor {2{n_{l_{i}^{\prime}}/3}} \right\rfloor} \right){mod}\mspace{14mu} n_{l_{i}^{\prime}}} & {i = 2}\end{matrix} \right.$

-   -   -   otherwise.

    -   9) Increase m′ by 1.

    -   10) Repeat from step 5 until all PHICH mapping units have been        assigned.        The PHICH duration is configurable by higher layers according to        Table 6.9.3-1 [which is reproduced as FIG. 9 of the present        application].

Demodulation Reference Signal (DMRS) is the reference signal to helpUE(s) demodulate EPDCCH (Enhanced Physical Downlink Control Channel) orPDSCH. DMRS is carried by four symbols in a subframe while the locationof the four symbols depends on cyclic-prefix (CP) length and subframetype. As an example, for the case of FDD cell with normal CP, DMRS iscarried by the last two symbols of both slots in a subframe, asdiscussed in 3GPP TS 36.211:

6.10.3.2 Mapping to Resource Elements

For antenna ports p=7, p=8 or p=7, 8, . . . , v+6, in a physicalresource block with frequency-domain index n_(PRB) assigned for thecorresponding PDSCH transmission, a part of the reference signalsequence r(m) shall be mapped to complex-valued modulation symbolsa_(k,l) ^((p)) in a subframe according to

Normal Cyclic Prefix:

a _(k,l) ^((p)) w _(p)(l′)·r(3·l′·N _(RB) ^(max,DL)+3·n _(PRB) +m′)

where

${w_{p}(i)} = \left\{ {{\begin{matrix}{{\overset{\_}{w}}_{p}(i)} & {{\left( {m^{\prime} + n_{PRB}} \right){mod}\mspace{14mu} 2} = 0} \\{{\overset{\_}{w}}_{p}\left( {3 - i} \right)} & {{\left( {m^{\prime} + n_{PRB}} \right){mod}\mspace{14mu} 2} = 1}\end{matrix}k} = {{{5m^{\prime}} + {N_{sc}^{RB}n_{PRB}} + {k^{\prime}k^{\prime}}} = \left\{ {{\begin{matrix}1 & {p \in \left\{ {7,8,11,13} \right\}} \\0 & {p \in \left\{ {9,10,12,14} \right\}}\end{matrix}l} = \left\{ {{\begin{matrix}{{l^{\prime}\mspace{14mu} {mod}\mspace{14mu} 2} + 2} & {{{if}\mspace{14mu} {in}\mspace{14mu} a\mspace{14mu} {special}\mspace{14mu} {subframe}\mspace{14mu} {with}\mspace{14mu} {configuration}\mspace{14mu} 3},4,{8\mspace{14mu} {or}\mspace{14mu} 9\left( {{see}\mspace{14mu} {Table}\mspace{14mu} 4.2\text{-}1} \right)}} \\{{l^{\prime}\mspace{14mu} {mod}\mspace{14mu} 2} + 2 + {3\left\lfloor {l^{\prime}/2} \right\rfloor}} & {{{if}\mspace{14mu} {in}\mspace{14mu} a\mspace{14mu} {special}\mspace{14mu} {subframe}\mspace{14mu} {with}\mspace{14mu} {configuration}\mspace{14mu} 1},2,{6\mspace{14mu} {or}\mspace{14mu} 7\left( {{see}\mspace{14mu} {Table}\mspace{14mu} 4.2\text{-}1} \right)}} \\{{l^{\prime}\mspace{14mu} {mod}\mspace{14mu} 2} + 5} & {{if}\mspace{14mu} {not}\mspace{14mu} {in}\mspace{14mu} a\mspace{14mu} {special}\mspace{14mu} {subframe}}\end{matrix}l^{\prime}} = \left\{ {{{\begin{matrix}{0,1,2,3} & {\mspace{14mu} \begin{matrix}{{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {0\mspace{14mu} {and}\mspace{14mu} {in}\mspace{14mu} a\mspace{14mu} {special}\mspace{14mu} {subframe}}} \\{{{with}\mspace{14mu} {configuration}\mspace{14mu} 1},2,{6\mspace{14mu} {or}\mspace{14mu} 7\left( {{see}\mspace{14mu} {Table}\mspace{14mu} 4.2\text{-}1} \right)}}\end{matrix}} \\{0,1} & \begin{matrix}{{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {0\mspace{14mu} {and}\mspace{14mu} {not}\mspace{14mu} {in}\mspace{14mu} {special}\mspace{14mu} {subframe}}} \\{{{with}\mspace{14mu} {configuration}\mspace{14mu} 1},2,{6\mspace{14mu} {or}\mspace{14mu} 7\left( {{see}\mspace{14mu} {Table}\mspace{14mu} 4.2\text{-}1} \right)}}\end{matrix} \\{2,3} & \begin{matrix}{{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {1\mspace{14mu} {and}\mspace{14mu} {not}\mspace{14mu} {in}\mspace{14mu} {special}\mspace{14mu} {subframe}}} \\{{{with}\mspace{14mu} {configuration}\mspace{14mu} 1},2,{6\mspace{14mu} {or}\mspace{14mu} 7\left( {{see}\mspace{14mu} {Table}\mspace{14mu} 4.2\text{-}1} \right)}}\end{matrix}\end{matrix}m^{\prime}} = 0},1,2} \right.} \right.} \right.}} \right.$

The sequence w _(p) (i) is given by Table 6.10.3.2-1 [which isreproduced as FIG. 10 of the present application].

Extended Cyclic Prefix:

a _(k,l) ^((p)) =w _(p)(l′ mod 2)·r(4·l′·N _(RB) ^(max,DL)+4·n _(PRB)+m′)

where

$\begin{matrix}{\mspace{79mu} {{w_{p}(i)} = \left\{ {{\begin{matrix}{{\overset{\_}{w}}_{p}(i)} & {{m^{\prime}\mspace{14mu} {mod}\mspace{14mu} 2} = 0} \\{{\overset{\_}{w}}_{p}\left( {1 - i} \right)} & {{m^{\prime}\mspace{14mu} {mod}\mspace{14mu} 2} = 1}\end{matrix}\mspace{79mu} k} = {{{3m^{\prime}} + {N_{sc}^{RB}n_{PRB}} + {k^{\prime}\mspace{79mu} k^{\prime}}} = \left\{ {{\begin{matrix}1 & {{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {{0\mspace{14mu} {and}\mspace{14mu} p} \in \left\{ {7,8} \right\}}} \\2 & {{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {{1\mspace{14mu} {and}\mspace{14mu} p} \in \left\{ {7,8} \right\}}}\end{matrix}\mspace{79mu} l} = {{{l^{\prime}\mspace{14mu} {mod}\mspace{14mu} 2} + {4l^{\prime}}} = \left\{ \begin{matrix}{0,1} & {\mspace{14mu} \begin{matrix}{{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {0\mspace{14mu} {and}\mspace{14mu} {in}\mspace{14mu} a\mspace{14mu} {special}\mspace{14mu} {subframe}}} \\{{{with}\mspace{14mu} {configuration}\mspace{14mu} 1},2,3,{5\mspace{14mu} {or}\mspace{14mu} 6\left( {{see}\mspace{14mu} {Table}\mspace{14mu} 4.2\text{-}1} \right)}}\end{matrix}} \\{0,1} & {{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {0\mspace{14mu} {and}\mspace{14mu} {not}\mspace{14mu} {in}\mspace{14mu} {special}\mspace{14mu} {subframe}}} \\{2,3} & {{{if}\mspace{14mu} n_{s}\mspace{14mu} {mod}\mspace{14mu} 2} = {1\mspace{14mu} {and}\mspace{14mu} {not}\mspace{14mu} {in}\mspace{14mu} {special}\mspace{14mu} {subframe}}}\end{matrix} \right.}} \right.}} \right.}} & \; \\{\mspace{79mu} {{m^{\prime} = 0},1,2,3}} & \;\end{matrix}$

The sequence w _(p)(i) is given by Table 6.10.3.2-2 [which is reproducedas FIG. 11 of the present invention.For extended cyclic prefix, UE-specific reference signals are notsupported on antenna ports 9 to 14.

Resource elements (k,l) used for transmission of UE-specific referencesignals to one UE on any of the antenna ports in the set s, where s={7,8, 11, 13} or s={9, 10, 12, 14} shall

-   -   not be used for transmission of PDSCH on any antenna port in the        same slot, and    -   not be used for UE-specific reference signals to the same UE on        any antenna port other than those in s in the same slot.

As for downlink data in LTE, it is transmitted on PDSCH and carried bysymbols excluding the first or first several symbols of a subframe, i.e.excluding the symbols which are (maybe) occupied by the physical controlchannels, as mentioned above and discussed in 3GPP TS 36. 211 asfollows:

6.4 Physical Downlink Shared Channel

The physical downlink shared channel shall be processed and mapped toresource elements as described in clause 6.3 with the followingadditions and exceptions:

-   -   In resource blocks in which UE-specific reference signals are        not transmitted, the PDSCH shall be transmitted on the same set        of antenna ports as the PBCH, which is one of {0}, {0, 1}, or        {0, 1, 2, 3}.    -   In resource blocks in which UE-specific reference signals are        transmitted, the PDSCH shall be transmitted on antenna port(s)        {5}, {7}, {8}, or pε{7, 8, . . . , v+6}, where v is the number        of layers used for transmission of the PDSCH.    -   If PDSCH is transmitted in MBSFN subframes as defined in 3GPP TS        36.213 [4], the PDSCH shall be transmitted on one or several of        antenna port(s) pε{7, 8, . . . , v+6}, where v is the number of        layers used for transmission of the PDSCH.    -   PDSCH is not mapped to resource elements used for UE-specific        reference signals associated with PDSCH    -   In mapping to resource elements, the positions of the        cell-specific reference signals are given by clause 6.10.1.2        with the number of antenna ports and the frequency shift of the        cell-specific reference signals derived as described in clause        6.10.1.2, unless other values for these parameters are provided        by clause 7.1.9 in 3GPP TS 36.213 [4], in which case these        values are used in the resource blocks indicated by the relevant        DCI.    -   If the DCI associated with the PDSCH uses the C-RNTI or        semi-persistent C-RNTI, the PDSCH is not mapped to resource        elements assumed by the UE to be used for transmission of:    -   zero-power CSI reference signals, where the positions of the CSI        reference signals are given by clause 6.10.5.2. The        configuration for zero power CSI reference signals is        -   obtained as described in clause 6.10.5.2, unless other            values for these parameters are provided by clause 7.1.9 in            3GPP TS 36.213 [4], in which case these values are used in            the resource blocks indicated by the relevant DCI, and        -   obtained by higher-layer configuration of up to five            reserved CSI-RS resources as part of the discovery signal            configuration following the procedure for zero-power CSI-RS            in clause 6.10.5.2.        -   non-zero-power CSI reference signals for CSI reporting,            where the positions of the non-zero-power CSI reference            signals for CSI reporting are given by clause 6.10.5.2. The            configuration for non-zero power CSI reference signals is            obtained as described in clause 6.10.5.2.    -   PDSCH is not mapped to any physical resource-block pair(s)        carrying an EPDCCH associated with the PDSCH.    -   The index l in the first slot in a subframe fulfils        l≧l_(DataStart) where l_(DataStart) is given by clause 7.1.6.4        of 3GPP TS 36.213 [4].    -   In mapping to resource elements, if the DCI associated with the        PDSCH uses the C-RNTI or semi-persistent C-RNTI and transmit        diversity according to clause 6.3.4.3 is used, resource elements        in an OFDM symbol assumed by the UE to contain CSI-RS shall be        used in the mapping if and only if all of the following criteria        are fulfilled:        -   there is an even number of resource elements for the OFDM            symbol in each resource block assigned for transmission, and        -   the complex-valued symbols y^((p))(i) and y^((p))(i+1),            where i is an even number, can be mapped to resource            elements (k,l) and (k+n,l) in the same OFDM symbol with n<3.

The concept of radio access for 5G is discussed in the DOCOMO 5G WhitePaper. One key point is to efficiently integrate both lower and higherfrequency bands. Higher frequency bands provide opportunities for widerspectrum but have coverage limitations because of higher path loss. TheDOCOMO 5G White Paper proposes that the 5G system has a two-layerstructure that consists of a coverage layer (e.g., consisting of macrocell(s)) and a capacity layer (e.g., consisting of small cell(s) orphantom cell(s)). The coverage layer uses existing lower frequency bandsto provide basic coverage and mobility. The capacity layer uses newhigher frequency bands to provide high data rate transmission. Thecoverage layer could be supported by enhanced LTE RAT while the capacitylayer could be supported by a new RAT dedicated to higher frequencybands. The efficient integration of the coverage and capacity layers isenabled by the tight interworking (dual connectivity) between theenhanced LTE RAT and the new RAT. In addition, a cell in 5G may containa single transmission point (TP)/transmission and reception point (TRP)or multiple TPs/TRPs and a network node (e.g., eNB) communicates withUEs in the cell via these TPs/TRPs.

As discussed in 3GPP TS 36.300, dual connectivity is a mode of operationof a UE in RRC_CONNECTED, configured with a Master Cell Group (i.e., agroup of serving cells associated with the MeNB (Master eNB), comprisingof the PCell and optionally one or more SCells) and a Secondary CellGroup (i.e., a group of serving cells associated with the SeNB(Secondary eNB), comprising of PSCell (Primary Secondary Cell) andoptionally one or more SCells). A UE configured with dual connectivitygenerally means that the UE is configured to utilize radio resourcesprovided by two distinct schedulers, located in two eNBs (MeNB and SeNB)connected via a non-ideal backhaul over the X2 interface. Furtherdetails of dual connectivity can be found in 3GPP TS 36.300.

In dual connectivity, the random access procedure is also performed onat least PSCell upon SCG (Secondary Cell Group) addition/modification(if instructed), upon DL data arrival during RRC_CONNECTED requiringrandom access procedure (e.g., when UL synchronisation status isnon-synchronized), or upon UL data arrival during RRC_CONNECTEDrequiring random access procedure (e.g., when UL synchronization statusis non-synchronized or there are no available PUCCH (Physical UplinkControl Channel) resources for SR. The UE-initiated random accessprocedure is performed only on PSCell for SCG.

The random access procedure has two different types: contention-basedand non-contention based. The contention based random access procedureis shown in FIG. 12, which is a reproduction of FIG. 10.1.5.1-1 of 3GPPTS 36.300. FIG. 12 includes the following four steps:

-   1. Random Access Preamble on RACH (Random Access Channel) mapped to    PRACH (Physical Random Access Channel) in uplink-   2. Random Access Response generated by MAC (Medium Access Channel)    on DL-SCH (Downlink Shared Channel)-   3. First scheduled UL (Uplink) transmission on UL-SCH (Uplink Shared    Channel)-   4. Contention Resolution on DL.

The non-contention based random access procedure is shown in FIG. 13,which is a reproduction of FIG. 10.1.5.2-1 of 3GPP TS 36.300. FIG. 13includes the following three steps:

-   0. Dedicated Random Access Preamble assignment via dedicated    signalling in DL-   1. Non-contention Random Access Preamble on RACH mapped to PRACH in    uplink-   2. Random Access Response on DL-SCH

Details of each step in a random access procedure can be found in 3GPPTS 36.300 and 36.321.

Regarding frame structure for the next generation radio accesstechnology, a TDD optimized physical subframe structure for a UDN systemproposed by METIS Deliverable D2.4 is illustrated in FIG. 14, followingthese main design principles:

-   -   A bi-directional (including both DL and UL resources) control        part is embedded to the beginning of each subframe and        time-separated from data part.    -   Data part in one subframe contains data symbols for either        transmission or reception. Demodulation reference signal (DMRS)        symbols, which used to estimate the channel and its covariance        matrix, could be located in the first OFDM symbol in the dynamic        data part and could be precoded with the same vector/matrix as        data.    -   Short subframe lengths (e.g., 0.25 ms on cmW frequencies when        assuming 60 kHz SC spacing) are feasible. By following the        principles of harmonized OFDM concept, the frame numerology is        further scaled when moving to mmW, leading to even shorter frame        length (e.g., in the order of 50 μs).    -   In frequency direction, the spectrum can be divided to separate        allocable frequency resources.

Furthermore, cells on the capacity layer may use beamforming.Beamforming is generally a signal processing technique used in antennaarrays for directional signal transmission or reception. This isachieved by combining elements in a phased array in such a way thatsignals at particular angles experience constructive interference whileothers experience destructive interference. Beamforming could be used atboth the transmitting and receiving ends to achieve spatial selectivity.The improvement compared with omnidirectional reception/transmission isknown as the receive/transmit gain.

Beamforming is frequently applied in radar systems. The beam created bya phased array radar is comparatively narrow and highly agile comparedto a moving dish. This characteristic gives the radar the ability todetect small, fast targets like ballistic missiles in addition toaircrafts.

The benefit of co-channel interference reduction also makes beamformingattractive to a mobile communication system designer. U.S. ProvisionalApplication Ser. No. 62/107,814, entitled “Method and Apparatus for BeamTracking in a Wireless Communication System”, generally discloses theconcept of beam division multiple access (BDMA) based on beamformingtechnique. In BDMA, a base station could communicate with a mobiledevice via a narrow beam to obtain the receive/transmit gain.Furthermore, two mobile devices in different beams could share the sameradio resources at the same time; and thus the capacity of a mobilecommunication system can increase greatly. To achieve that, the basestation should know in which beam a mobile device is located.

A cell, transmission point (TP), or transmission and reception point(TRP) could use beamforming for directional signal transmission orreception. Due to power saving or hardware limitation (e.g.,insufficient number of transceivers), the cell, TP, or TRP may not beable to generate all beams to cover all directions within the coverageof the cell, TP, or TRP. In other words, the cell, TP, or TRP maygenerate part of the beams for directional signal transmission orreception at a time. For example, the maximum number of beams which canbe generated by a cell, TP, or TRP at one time could be less than thetotal number of beams in the cell or the total number of beams of the TPor TRP. At the same time, directional signal transmission or receptionon other non-generated beams would be impossible. Thus, it would takemultiple times for a cell, TP, or TRP to scan all beams of the cell, TP,or TRP.

The downlink control signaling can generally be categorized into 2types:

-   -   Type 1—Common signaling (transmitted periodically) intended for        all or plurality of UEs in the cell or UEs connecting to the TP        or TRP (e.g., system information, PSS/SSS, CRS, control        signaling for broadcast message, etc.)    -   Type 2:—UE specific signaling (transmitted dynamically or        periodically), e.g., PDCCH, PHICH, DMRS, etc.

If the cell, TP, or TRP has limitation of beam generation as describedabove, it is assumed that type 1 signaling is transmitted on predefinedbeams in a specific timing (e.g., subframe(s) or symbol(s)). As aresult, transmissions (e.g., type 2 control signaling or data) to UEsnot covered by the predefined beams in the same specific timing would beimpossible. Then, network scheduling flexibility is limited. Designing aframe structure to improve network scheduling flexibility should beconsidered.

Communication between a network node and a UE could be organized intoframes. A frame could contain multiple subframes. A subframe couldcontain multiple symbols. A subframe could contain a downlink controlregion which contains one or multiple symbols and is used to carrycontrol signaling.

FIG. 15 is a diagram of a subframe 1500 in according with one exemplaryembodiment. In general, the concept of the invention is that in downlinkcontrol region 1505 of a subframe, there is at least a first part of thedownlink control region (e.g., consisting of at least one symbol) usedto transmit UE specific downlink control signaling (e.g., type 2) 1510,and not used to transmit common downlink control signaling (e.g., type1). Then, the network could flexibly use the first part of downlinkcontrol region to transmit signaling on beam(s) of certain UE(s), and isnot limited by the beams for type 1 signaling.

In addition, there could be a second part of the downlink control region(e.g., consisting of at least one symbol) used to transmit commondownlink control signaling (e.g., type 1) 1515. The second part couldalso be used to transmit UE specific downlink control signaling (e.g.,type 2) if the associated UE is covered by predefined beams used fortransmitting the type 1 signaling. Alternatively, the second part couldnot be used to transmit UE specific downlink control signaling (e.g.,type 2). The subframe 1500 could also include a data region 1520.

Furthermore, the UE specific downlink control signaling (e.g., for onespecific UE) could include at least one of the following signals orsignalings:

-   -   A signaling (e.g., on PDCCH) to allocate resource for a DL or UL        transmission;    -   A signaling (e.g., on PHICH) to carry HARQ feedback in response        to at least one UL transmission; and/or    -   A reference signal used to help an UE demodulate a DL        transmission (e.g., DMRS).

In addition, the common downlink control signaling (e.g., for multipleUEs) could include at least one of the following signals or signalings:

-   -   A signaling indicating system frame number of the cell, TP, or        TRP;    -   A signaling (e.g., on PDCCH) allocate resource for a broadcast        message (e.g., system information, paging, random access        response) for UE(s) in the cell or for UE(s) connecting to the        TP or TRP;    -   A synchronization signal for UE(s) in the cell or for UE(s)        connecting to the TP or TRP to obtain downlink timing; and/or    -   A reference signal for UE(s) to measure downlink radio condition        (e.g., CRS).

Also, every subframe with downlink control region could contain thefirst part and the second part. In one embodiment, beam(s) of the cell,TP, or TRP generated in the first part would be different from beam(s)of the cell, TP, or TRP generated in the second part.

In addition, the general concept of the invention could be applied tothe LTE frame structure (discussed in 3GPP TS 36.300). Alternatively,the concept could be applied to the METIS frame structure (discussed inMETIS Deliverable D2.4).

Another general concept of the invention is that in downlink controlregion of a subframe, there is at least a first part of the downlinkcontrol region (e.g., consisting of at least one symbol) and a secondpart of the downlink control region (e.g., consisting of at least onesymbol), wherein beam(s) of the cell, TP, or TRP generated in the firstpart is completely or partially different from beam(s) of the cell, TP,or TRP generated in the second part.

In one embodiment, the first part could be used to transmit the commondownlink control signaling (e.g., type 1) and/or the UE specificdownlink control signaling (e.g., type 2). Similarly, the second partcould be used to transmit the common downlink control signaling (e.g.,type 1) and/or the UE specific downlink control signaling (e.g., type2).

In one embodiment, the subframe could contain a data region for UL, adata region for DL, and/or an uplink control region. The data regioncould also contain symbols, wherein beam(s) of the cell, TP, or TRPgenerated in different symbols is completely or partially different.

Furthermore, a signaling transmitted in the first part of the downlinkcontrol region of the subframe could be associated with resources infirst symbol(s) of the data region in the subframe; and a signalingtransmitted in the second part of the downlink control region of thesubframe could be associated with resources in second symbol(s) of thedata region in the subframe. The first symbol(s) and the secondsymbol(s) are completely or partially different.

In addition, the common downlink control signaling in the first part andthe common downlink control signaling in the second part could besynchronization signals with different sequences. The UE could detectthe subframe boundary according to the sequence used by thesynchronization signals.

Also, the common downlink control signaling in the first part and thecommon downlink control signaling in the second part could besynchronization signals on different frequency resources. The UE coulddetect the subframe boundary according to the frequency resources usedby the synchronization signals.

Also, the common downlink control signaling in the first part and thecommon downlink control signaling in the second part could betransmitted on different frequency resources.

FIG. 16 is a flow chart 1600 for defining a communication between acell, TP, or TRP and a UE in accordance with one exemplary embodiment.In step 1605, the communication is organized into radio frames, whereineach radio frame includes multiple subframes and each subframe includesmultiple symbols. In step 1610, a downlink control region is included ina subframe. In step 1615, a first symbol is included in the downlinkcontrol region, wherein the first symbol is used to carry a UE specificsignal and is not used to carry a common signal.

In one embodiment, the downlink control region could include a secondsymbol, wherein the second symbol is used to carry the common signal.Furthermore, the second symbol is used to carry the UE specific signal.Alternatively, the second symbol is not used to carry the UE specificsignal.

Referring back to FIGS. 3 and 4, in one exemplary embodiment fordefining a communication between a cell, TP, or TRP and a UE, the device300 includes a program code 312 stored in the memory 310. The CPU 308could execute program code 312 (i) to organize the communication intoradio frames, wherein each radio frame includes multiple subframes andeach subframe includes multiple symbols, (ii) to include a downlinkcontrol region in a subframe, and (iii) to include a first symbol in thedownlink control region, wherein the first symbol is used to carry a UEspecific signal and is not used to carry a common signal. Furthermore,the CPU 308 can execute the program code 312 to perform all of theabove-described actions and steps or others described herein.

FIG. 17 is a flow chart 1700 from the perspective of a network nodecontrolling a cell, TP, or TRP in accordance with one exemplaryembodiment. Step 1705 includes communicating with a UE in the cell viadownlink and uplink transmissions, wherein the downlink and uplinktransmissions are organized into radio frames and each radio framecontains multiple subframes and each subframe contains multiple symbols.Step 1710 includes transmitting, in the cell, a UE specific signal in afirst symbol of a downlink control region of a subframe of the multiplesubframes, wherein the network node is not allowed to transmit a commonsignal in the first symbol.

In one embodiment, as shown in step 1715, the network node transmits, inthe cell, the common signal in a second symbol of the downlink controlregion. Furthermore, as shown in step 1720, the network node transmitsthe UE specific signal in the second symbol. Alternatively, the networknode is not allowed to transmit the UE specific signal in the secondsymbol.

Referring back to FIGS. 3 and 4, in one embodiment from the perspectiveof a network node controlling a cell, TP, or TRP, the device 300includes a program code 312 stored in memory 310. The CPU 308 couldexecute program code 312 to enable the network node (i) to communicatewith a UE in the cell via downlink and uplink transmissions, wherein thedownlink and uplink transmissions are organized into radio frames andeach radio frame contains multiple subframes and each subframe containsmultiple symbols, and (ii) to transmit, in the cell, a UE specificsignal in a first symbol of a downlink control region of a subframe ofthe multiple subframes, wherein the network node is not allowed totransmit a common signal in the first symbol. In one embodiment, the CPUcould further execute program code 312 to enable the network node (i) totransmits, in the cell, the common signal in a second symbol of thedownlink control region, and/or (ii) to transmit the UE specific signalin the second symbol. Furthermore, the CPU 308 can execute the programcode 312 to perform all of the above-described actions and steps orothers described herein.

FIG. 18 is a flow chart 1800 in accordance with one exemplary embodimentfrom the perspective of a UE. In step 1805, the UE communicates with anetwork node in a cell via downlink and uplink transmissions, whereinthe downlink and uplink transmissions are organized into radio frames,each radio frame includes multiple subframes, and each subframe includesmultiple symbols. In step 1810, the UE monitors, in the cell, a UEspecific signal in a first symbol of a downlink control region of asubframe, and not monitoring a common signal in the first symbol.

In one embodiment, as shown in step 1815, the UE could monitor, in thecell, the common signal in a second symbol of the downlink controlregion. Furthermore, as shown in step 1820, the UE could monitor the UEspecific signal in the second symbol. Alternatively, the UE does notmonitor the UE specific signal in the second symbol.

Referring back to FIGS. 3 and 4, in one embodiment from the perspectiveof a UE, the device 300 includes a program code 312 stored in memory 310of the transmitter. The CPU 308 could execute program code 312 to enablethe UE (i) to communicate with a network node in a cell via downlink anduplink transmissions, wherein the downlink and uplink transmissions areorganized into radio frames, each radio frame includes multiplesubframes, and each subframe includes multiple symbols, and (ii) tomonitor, in the cell, a UE specific signal in a first symbol of adownlink control region of a subframe, and not monitoring a commonsignal in the first symbol. In one embodiment, the CPU could furtherexecute program code 312 to enable the network node (i) to monitor, inthe cell, the common signal in a second symbol of the downlink controlregion, and/or (ii) to monitor the UE specific signal in the secondsymbol. In addition, the CPU 308 can execute the program code 312 toperform all of the above-described actions and steps or others describedherein.

With respect to the various embodiments disclosed and discussed, thesubframe could include a data region for UL, a data region for DL,and/or an UL control region in one embodiment. Besides, the network nodecould be a base station.

Furthermore, in one embodiment, the UE specific signal could be for onespecific UE. In addition, the UE specific signal could be transmitted onbeam(s) of the cell, TP, or TRP corresponding to the UE. Also, the UEspecific signal could be a signaling indicating resource allocation(e.g., PDCCH), a signaling indicating HARQ feedback (e.g.,PHICH—“Physical Hybrid ARQ Indicator Channel”), and/or a referencesignal for demodulation (e.g., DMRS). Furthermore, the UE specificsignal could be associated with a UE specific reference signal (e.g.,DMRS). In addition, the UE specific signal could be demodulated based onreception of a UE specific reference signal (e.g., DMRS).

In one embodiment, the common signal is for multiple UEs. The commonsignal is to be transmitted on every beam of the cell, TP, or TRP. Inaddition, the common signal could be a signaling indicating a systemframe number (SFN), a signaling (e.g., on PDCCH) indicating resourceallocation for a broadcast message (e.g., system information, paging,random access response) for UE(s) in the cell or for UE(s) connecting tothe TP or TRP, a synchronization signal (e.g., a PSS or a SSS), and/or areference signal for DL radio condition measurement (e.g., CRS).Furthermore, the common signal could be associated with a commonreference signal (e.g., CRS). Also, the common signal could bedemodulated based on reception of a common reference signal (e.g., CRS).

In one embodiment, all of the multiple subframes (for DL) could have thefirst symbol. Alternatively, not all of the multiple subframes (for DL)have the first symbol. In another embodiment, all of the multiplesubframes (for DL) could have the second symbol. Alternatively, not allof the multiple subframes (for DL) have the second symbol

In one embodiment, the first symbol could be in front of the secondsymbol in the subframe. Alternatively, the second symbol could be infront of the first symbol in the subframe.

In one embodiment, beam(s) of the cell, TP, or TRP generated in thefirst symbol is different from beam(s) generated in the second symbol.In one embodiment, the symbol could be an OFDM (Orthogonal FrequencyDivision Multiplexing) symbol.

As discussed above, a cell, TP, or TRP on the capacity layer may usebeamforming for directional signal transmission or reception. To performbeamforming with a UE in the cell or a UE connecting to the TP or TRP, abase station should know which beam(s) of the cell, TP, or TRP the UE islocated on, e.g. beam set of the UE. It is proposed in METIS Deliverable2.4 that a UE transmits its position and speed to the base station andthen the base station determines the direction of a downlink beam forthe mobile device according to the received position and speed. However,information of the position and speed is not always available andreliable in the UE. Thus, it would better to find another way for thebase station to determine the beam set of a UE.

Currently as discussed in 3GPP TS 36.300 and 36.331, a random access(RA) procedure needs to be performed by a UE before data can betransferred via a cell, TP, or TRP. One possible way is that the basestation could determine the initial beam set of a UE during the RAprocedure, e.g., the beam set could be determined according to thebeam(s) via which the dedicated RA preambles are received from the UE.However, with this method the base station needs to process thepreambles on all beams of the cell, TP, or TRP, which would result in avery high system load. Therefore, it would be simpler to use a referencesignal (RS) for beam set determination, i.e., the UE transmits thereference signal in the cell or to the TP or TRP. And the RA procedurecould be initiated after the initial UE beam set has been determined. Inthis situation, the base station would only need to process thepreamble(s) on the beam(s) in the UE beam set. It is expected that thebeam number of a UE beam set (e.g., 4) would be much less than the totalnumber of beams for one cell, TP, or TRP (e.g., 32, 64, or more). As aresult, signal processing complexity could be reduced significantly.

According to the above concept, a random access (RA) procedure will beinitiated after the beam set of a UE has been determined. One possibleway to initiate the RA procedure is that the base station could transmita request to the UE via the beam set of the UE to initiate the RAprocedure. However, delay compensation (e.g., of a downlink transmissionon different beams to the UE) would be required when the downlinktransmission is performed via multiple beams. Otherwise, the UE may notbe able to successfully decode the downlink transmission (e.g.,including the request to initiate the RA procedure). Furthermore, itdoes not seem feasible for the base station to measure the delay of eachbeam based on the RS used for beam set determination. Therefore, a meansor mechanism to let the UE initiate a random access procedure on thecell or to access the TP or TRP at proper timing should be considered.

The general concept of the invention is that a first base station (e.g.,MeNB) controlling a first cell, TP, or TRP (e.g., in coverage layer)could provide configuration of a timer (or a counter) to a UE via thefirst cell, TP, or TRP. The UE would decide the timing to initiate arandom access procedure (or to transmit a random access preamble) on asecond cell or to access a second TP or TRP (e.g., in capacity layer)controlled by a second base station (e.g., SeNB) based on at least thetimer (or the counter).

In one embodiment, the configuration could be included in a signaling.The signaling is a RRC message, e.g., a RRCConnectionReconfigurationmessage as discussed in 3GPP TS 36.331. The signaling could configurethe UE to perform dual connectivity. The signaling could also be used toconfigure the second cell, TP, or TRP as a serving cell, TP, or TRP ofthe UE.

In addition, the signaling could also configure the UE to transmit asignal in the second cell or to the second TP or TRP. The signal couldbe transmitted periodically. The signal could be used to help the secondbase station detect beam(s) of the second cell, TP, or TRP for the UE.In one embodiment, the signal could be a reference signal (RS).

In one embodiment, the UE could start the timer (i) upon reception ofthe configuration, (ii) upon transmission of the signal (if the timer isnot running), (iii) upon first transmission of the signal, or (iv) uponcompletion of synchronizing to the second cell, TP, or TRP. The countercould also be used to count transmission times of the signal.

In one embodiment, the UE could (i) initiate the random access procedureupon the timer expiry, (ii) transmit a random access preamble inresponse to the timer expiry, (iii) initiate the random access procedureupon reaching the maximum value of the counter, or (iv) transmit arandom access preamble in response to reaching the maximum value of thecounter.

In one embodiment, the uplink time of the UE is not aligned in thesecond cell, TP, or TRP (e.g., timeAlignmentTimer, as discussed in 3GPPTS 36.321, associated with the second cell, TP, or TRP is not running).

An alternative concept of the invention is that a second base station(e.g., SeNB) controlling a second cell, TP, or TRP (e.g., in capacitylayer) determines beams of the second cell, TP, or TRP for a UE (i.e., abeam set for the UE). The second base station selects (only) one beam inthe beam set (i.e., a first beam), and transmits a request (e.g., PDCCHorder as discussed in 3GPP TS 36.321) on the first beam to the UE toinitiate a random access procedure on the second cell or to access thesecond TP or TRP.

In one embodiment, the beam set includes multiple beams where a signalfrom the UE in the second cell or to the second TP or TRP has beendetected. The first beam is where the signal has been detected with thelargest received power. Received power of the signal on the first beamis larger than a threshold. Received power of the signal on multiplebeams of the beam set is larger than the threshold. The signal could bea reference signal.

In one embodiment, delay compensation for beams in the beam set is notdetermined when transmitting the request. In other words, before delaycompensation for beams in the beam set is determined, the second basestation selects only one beam in the beam set for transmission to theUE. After delay compensation for beams in the beam set is determined,the second base station could select multiple beams in the beam set fortransmission to the UE. Uplink time of the UE is not aligned in thesecond cell, TP, or TRP (e.g. timeAlignmentTimer, as discussed in 3GPPTS 36.321, associated with the second cell, TP, or TRP is not running,when transmitting the request).

FIG. 19 is a message diagram 1900 in accordance with one embodiment. Instep 1905, the UE receives a signaling indicating a configurationrelated to a timer or a counter. In step 1910, the UE initiates a randomaccess procedure based on the timer or the counter. In one embodiment,the random access procedure is initiated on a second cell or isinitiated to access a second TP or TRP. Furthermore, the random accessprocedure could be initiated upon expiry of the timer or upon reaching aspecific value of the counter.

FIG. 20 is a message diagram 2000 in accordance with one embodiment. Instep 2005, the UE receives a signaling indicating a configurationrelated to a timer or a counter. In step 2010, the UE transmits a randomaccess preamble based on at least the timer or the counter. In oneembodiment, the random access preamble is transmitted in a second cellor is transmitted to a second TP or TRP. Furthermore, the random accesspreamble could be transmitted in response to expiry of the timer, or inresponse to reaching a specific value of the counter.

With respect to the embodiments illustrated in FIGS. 19 and 20 anddiscussed above, the configuration could indicate a value of the timeror maximum value of the counter. Furthermore, the second cell, TP, orTRP could be controlled by a second base station. In addition, thesignaling could be transmitted in a first cell or is transmitted to afirst TP or TRP.

In one embodiment, the signaling could be transmitted by a first basestation to control when the UE initiates the random access procedure ortransmits the random access preamble. The first cell, TP, or TRP couldbe controlled by the first base station. Furthermore, the first basestation could be an eNB (e.g., MeNB).

In one embodiment, the timer could be maintained by the UE. Furthermore,the timer could be started upon reception of the signaling, upontransmission of a specific signal (if the timer is not running), or uponfirst transmission of the specific signal.

In one embodiment, the counter is maintained by the UE. Furthermore, thecounter is related to transmission times of a specific signal. Thecounter could be set to 0 upon reception of the signaling or upon firsttransmission of a specific signal.

In one embodiment, the signaling could indicate a configuration relatedto the specific signal, e.g. resource and/or periodicity. Furthermore,the signaling could tell the UE to perform dual connectivity. Inaddition, the signaling could indicate addition of the second cell, TP,or TRP as a serving cell, TP, or TRP of the UE. In one embodiment, thesignaling could be a RRC message or a RRCConnectionReconfigurationmessage.

FIG. 21 is a message diagram 2100 in accordance with one embodiment fromthe perspective of a second base station controlling a second cell, TP,or TRP. In step 2105, a beam set for a UE is determined, wherein thebeam set includes multiple beams. In step 2110, a first beam (B_(x)) isselected from the beam set. In step 2115, a request, which is used toask the UE to initiate a random access procedure on the second cell orto access the second TP or TRP, is transmitted only on the first beam(B_(x)) to the UE. In one embodiment, the request could be a PDCCHorder.

In one embodiment, beams in the beam set could be where a specificsignal from the UE is received. Furthermore, beams in the beam set couldbe where a specific signal from the UE is received with a received powerof the specific signal is larger than a first threshold.

In one embodiment, the beam set could be determined based on at leastreception of a specific signal from the UE in the second cell or fromthe UE to the second TP or TRP. Furthermore, a specific signal could bereceived from the UE on the first beam with the largest received power.In addition, the first beam could be selected from the beam set based ona received power of a specific signal from the UE. The received power ofa specific signal from the UE on the first beam could be larger than asecond threshold. Also, the received power of a specific signal from theUE on multiple beams in the beam set could be larger than a secondthreshold. Furthermore, the second threshold could be larger than thefirst threshold.

In one embodiment, delay compensation of downlink transmission(s) to theUE for beams in the beam set is not determined.

With respect to the embodiments illustrated in FIGS. 19, 20, and 21 anddiscussed above, the random access procedure could be non-contentionbased. Furthermore, the random access procedure could be successfullycompleted in response to reception of a Timing Advance Command (e.g., ina MAC control element as discussed in 3GPP TS 36.321).

In one embodiment, the second cell, TP, or TRP uses beamforming.Furthermore, the second cell, TP, or TRP could have multiple beams. Inaddition, the UE could perform dual connectivity to connect to multiplecells, TPs, TRPs, or base stations.

In one embodiment, the specific signal could be transmittedperiodically. Furthermore, the specific signal could be a referencesignal (e.g., SRS as discussed in 3GPP TS 36.213). In addition, thespecific signal could be transmitted in the second cell, or could betransmitted to the second TP or TRP.

In one embodiment, the specific signal is used to identify a beam setfor the UE. In addition, the uplink timing of the UE is not aligned(e.g., in the second cell, TP, or TRP).

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

1. A method for a network node controlling a cell, comprising:communicating with a UE (User Equipment) in the cell via downlink anduplink transmissions, wherein the downlink and uplink transmissions areorganized into radio frames and each radio frame contains multiplesubframes and each subframe contains multiple symbols; and transmitting,in the cell, a UE specific signal in a first symbol of a downlinkcontrol region of a subframe of the multiple subframes, wherein thenetwork node is not allowed to transmit a common signal in the firstsymbol.
 2. The method of claim 1, wherein the network node transmits, inthe cell, the common signal in a second symbol of the downlink controlregion.
 3. The method of claim 2, wherein the network node transmits theUE specific signal in the second symbol.
 4. The method of claim 1,wherein the subframe includes a data region for uplink (UL), a dataregion for downlink (DL), and/or an UL control region.
 5. The method ofclaim 1, wherein the UE specific signal is a signaling indicatingresource allocation, a signaling indicating HARQ (Hybrid AutomaticRepeat reQuest) feedback, and/or a reference signal for demodulation. 6.The method of claim 1, wherein the common signal is a signalingindicating a system frame number (SFN), a signaling indicating resourceallocation for a broadcast message, a synchronization signal, or areference signal for DL radio condition measurement.
 7. The method ofclaim 1, wherein beam(s) of the cell generated in the first symbol isdifferent from beam(s) generated in the second symbol.
 8. A method for aUser Equipment (UE), comprising: communicating with a network node in acell via downlink and uplink transmissions, wherein the downlink anduplink transmissions are organized into radio frames, each radio frameincludes multiple subframes, and each subframe includes multiplesymbols; and monitoring, in the cell, a UE specific signal in a firstsymbol of a downlink control region of a subframe, and not monitoring acommon signal in the first symbol.
 9. The method of claim 8, wherein theUE monitors, in the cell, the common signal in a second symbol of thedownlink control region.
 10. The method of claim 9, wherein the UEmonitors the UE specific signal in the second symbol.
 11. The method ofclaim 8, wherein the subframe includes a data region for uplink (UL), adata region for downlink (DL), and/or an UL control region.
 12. Themethod of claim 8, wherein the UE specific signal is a signalingindicating resource allocation, a signaling indicating HARQ (HybridAutomatic Repeat reQuest) feedback, and/or a reference signal fordemodulation.
 13. The method of claim 8, wherein the common signal is asignaling indicating a system frame number (SFN), a signaling indicatingresource allocation for a broadcast message, a synchronization signal,or a reference signal for DL radio condition measurement.
 14. The methodof claim 8, wherein beam(s) of the cell generated in the first symbol isdifferent from beam(s) generated in the second symbol.
 15. A UserEquipment (UE) for communication with a network node, comprising: acontrol circuit; a processor installed in the control circuit; and amemory installed in the control circuit and operatively coupled to theprocessor; wherein the processor is configured to execute a program codestored in the memory to: communicate with the network node in a cell viadownlink and uplink transmissions, wherein the downlink and uplinktransmissions are organized into radio frames, each radio frame includesmultiple subframes, and each subframe includes multiple symbols; andmonitor, in the cell, a UE specific signal in a first symbol of adownlink control region of a subframe, and not monitoring a commonsignal in the first symbol.
 16. The UE of claim 15, wherein the UEmonitors, in the cell, the common signal in a second symbol of thedownlink control region.
 17. The UE of claim 16, wherein the UE monitorsthe UE specific signal in the second symbol.
 18. The UE of claim 15,wherein the UE specific signal is a signaling indicating resourceallocation, a signaling indicating HARQ (Hybrid Automatic RepeatreQuest) feedback, and/or a reference signal for demodulation.
 19. TheUE of claim 15, wherein the common signal is a signaling indicating asystem frame number (SFN), a signaling indicating resource allocationfor a broadcast message, a synchronization signal, or a reference signalfor DL radio condition measurement.
 20. The UE of claim 15, whereinbeam(s) of the cell generated in the first symbol is different frombeam(s) generated in the second symbol.